JP2003529785A - Electrodes for liquid crystal cells - Google Patents

Abstract

Abstract: Electrodes for liquid crystal cells include a substrate, for example, a glass having a conductive and alignment coating, such as a fluorine-doped tin oxide coating. After the conductive coating has been deposited on the substrate, its surface is cleaned and unidirectionally wiped with a cloth saturated with solvent for a predetermined time. In the electrode manufactured by the above method, it is not necessary to cover the entire surface of the conductive coating with the polyimide layer and to heat-treat the polyimide layer.

Description

Detailed Description of the Invention

    (Related application)

This application was filed on June 10, 1999 by Patricia Ruzakovsky Azei (
Patricia Ruzakowski Athey) US provisional patent application No. 60/13
Claim the benefit of the filing date of No. 8,481.

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to liquid crystal cells, and more particularly to electrodes for use in liquid crystal cells.

Consideration of Currently Available Technology Electrodes for liquid crystal cells are currently a conductive film or coating, usually an indium tin oxide (“ITO”) film, in a pair of electrodes, eg, two electrodes. It is manufactured by depositing on the surface of a glass plate. Liquefied polyimide is spin-coated on the ITO surface and heat treated to provide a polyimide coating on the ITO coating. After that, the surface of the polyimide layer of each of the electrodes is rubbed with a felt cloth in the same direction. Although the rubbing mechanism is not completely known, rubbing the surface of this polyimide layer with a felt cloth is carried out in order to orient the longitudinal axis of the liquid crystal in the liquid mixture contained between the electrodes in one preferred orientation. Be seen.
More specifically, when the liquid crystals are aligned parallel to the substrate surface and unidirectional with respect to each other, there is a homogeneous alignment. When the liquid crystal is vertically aligned with the substrate surface, it has a homeotropic alignment.
) Exists. For a discussion of polyimide layers, see Applied Physics Letter, 66 (17
), Published on April 24, 1995, Y. B. YB Kinn, H.K.
H. Olin, S.M. Y. SY Park, J.P. W. Choi (JW C
hoi), L.H. L. Komito, M.M. M. Mtusyzyh and S
． T. The article name by ST Lngewell, "RUBBED POLYIMIDE FILMS STUDIED BY SCANNING FORCE
MICROSCOPY) ”.

Liquid crystal cells are currently fabricated by suspending glass fibers and / or polymer beads in alcohol and spinning the alcohol-spacer mixture onto one of the electrodes. The electrodes are attached so that the polyimide surfaces face each other with their rubbing directions opposite to each other. The electrodes are held by a spacer in a positional relationship at regular intervals. The pair of opposing sides of the electrodes are sealed to provide a compartment between the abrading surfaces of the polyimide layer. The compartment is heated to a temperature above the isotropic temperature of the liquid crystal, eg about 90 ° C., and is capillary filled with a heated mixture containing nematic liquid crystal. The nematic liquid crystals can also include chiral nematic liquid crystals or chiral components (“liquid mixtures”). The liquid mixture can also contain a dichroic dye which provides a guest-host liquid crystal cell. The liquid mixture is preferably heated to a temperature above the isotropic temperature of the liquid crystal mixture. Mol. Cryst. Liq. Cryst., 68, 1981, 127-135. Garagedagi (F. G
haradjedaghi) titled "A POSITIVE CONTRAST GUEST-HOST D using a liquid crystal with negative dielectric anisotropy.
ISPLAY USING A LIQUID CRYSTAL OF NEGATIVE DIELECTRIC ANISOTROPY) "
Discussing liquid mixtures. After the compartment is capillary filled, the remaining open sides are sealed.

An AC voltage applied across the two electrodes changes the position of the longitudinal axis of the liquid crystal in the liquid mixture with respect to the electrode surface. For example, when an AC voltage is applied across both electrodes, the vertical axis of the liquid crystal is oriented. For example, in the case of a liquid crystal having a positive dielectric anisotropy, the applied voltage aligns the long axis of the liquid crystal parallel to the applied field, and in the liquid crystal having a negative dielectric anisotropy, the applied field Aligns the long axis of the liquid crystal perpendicular to and / or away from the applied field. The dichroic dye can have a positive or negative dichroic ratio. A dichroic dye having a positive dichroic ratio absorbs more light along the long axis of its molecule, and vice versa. In the case of guest-host nematic liquid crystal cells, when an AC voltage is applied across the electrodes, the liquid crystal (positive dielectric anisotropy) is aligned parallel to the applied field and the dichroic dye (positive dichroic dye Ratio) follows the orientation of the liquid crystal and advances the cell from a darkened state (off state) to a bleached state (on state). When the voltage is turned off, the liquid crystal and dichroic dye in the liquid crystal mixture are realigned parallel to the polyimide coating, making the liquid crystal cell less transparent, ie darker. US Pat. No. 5,477,358 discusses the manufacture and operation of liquid crystal cells.

As will be appreciated by those skilled in the art of processing liquid crystal cells, it is desirable to provide a liquid crystal cell that does not require the use of a polyimide layer, thereby eliminating the polyimide layer deposition, heat treatment and abrasion treatment. Would be advantageous.

SUMMARY OF THE INVENTION The present invention relates to improved liquid crystal cells, and more particularly to improved electrodes for liquid crystal cells. The improved liquid crystal cell according to the invention comprises a pair of electrodes which are spaced apart from one another, the edges of which are sealed so that there is a closed compartment for containing the liquid mixture between them. It is of the type given. The electrodes improved according to the invention are of the type having a conductive coating, for example an ITO coating, on a glass substrate and a polyimide layer on the ITO coating. The polyimide layer has a unidirectional abrading surface, in which case the abrading surfaces of both polyimide layers are facing each other with their rubbing treatment directions opposite to each other. Without limiting the invention to this, the liquid mixtures used here and in the claims can comprise nematic liquid crystals and dichroic dyes, and also chiral liquid crystal components, chiral components, thermochromic components. Substances and / or pyrones, oxazines, fulgides and flumidides (fu
lgimides) -containing types of photochromic materials can also be included. Other photochromic materials that can be used in the practice of the present invention include C.I. B
． In the name of CB Greenberg, "ELECTRO-OPTICAL DEVICE AND V ELECTRO-OPTICAL DEVICE AND VARIABLE TRANSPARENT ARTICLE HAVING SUCH A DEVICE".
ARIABLE TRANSPARENT ARTICLE WITH SUCH DEVICE) ". Thermochromic materials that can be used in the practice of the present invention include absorbent, reflective as a result of temperature changes, as described in US Pat. Nos. 4,028,118 and 4,732,810. It shows changes in physical properties such as properties and refractive index. Without limiting the invention,
Dichroic dyes are mostly alone, in mixtures, or in mixtures with photochromic substances as optically active substances, due to their ability to absorb light of a particular polarization when they are molecularly aligned within the liquid crystal substance. But useful. Dichroic dyes that can be used in the practice of this invention include, but are not limited to, azo dyes and anthraquinone dyes. Other dichroic dyes suitable for use in the present invention include Congo red (diphenyl-bis-alpha-naphthylamine sodium sulfonate), methylene blue, stilbene dyes (chromaticity index (CI) = 62).
0) and 1,1′-diethyl-2,2′-cyanine chloride (CI = 374 (
Orange) or CI = 518 (blue)). The nature of these dyes and their method of preparation are described in E. H. EH Land Colloid Chemistry
emistry) (1946). These dyes have a pronounced dichroism in polyvinyl alcohol and less dichroism in cellulose. Other suitable dyes include Kirk Othmer Encyclopedia of Chemical Technology,
There are dyes discussed in Volume 8, pp. 652-661 (4th edition, 1993) and references cited therein, along with their properties and manufacturing methods.

The improved electrode of the present invention eliminates the need for a polyimide layer. More specifically, the electrode of the present invention has a conductive material deposited on a substrate, the conductive material having the properties of conductivity and alignment and / or alignment of liquid crystals of a liquid mixture in a compartment. ing. Conductive materials that can be used in the practice of the invention include, but are not limited to, conductive metal oxides deposited by pyrolysis,
For example, without limiting the invention, U.S. Pat. No. 4,584,206.
No. 4,900,100 and No. 5,356,718, as well as Janos Szanyi, filed on March 9, 2000 under the name of "low haze paint Methods of Making Low Haze Coatings, and the Coatings an
US Patent Application No. 09/521, entitled "D Coated Articles Made Through)"
There are tin oxides containing fluorine, antimony and mixtures thereof of the type disclosed in 845 (discloses Solarban 55 coated glass). The disclosures of the above US patents and patent applications are incorporated herein by reference.

The present invention further relates to a method of making the improved liquid crystal cell described above. The method includes the steps of providing a substrate having a conductive material, eg, pyrolytically depositing tin oxide doped with fluorine and / or antimony. The surface was wiped with a cloth saturated with alcoholic solvent
, It's clean. If the wiping is irregular, the transmitted color of the liquid crystal cell in the darkened state is uniform to the naked eye and exhibits an irregular wiping pattern when viewed through a linear polarizer. If the wiping is unidirectional, the transmitted color of the liquid crystal cell in the darkened state is uniform both with the naked eye and through the linear polarizer. A liquid crystal cell is assembled by mounting electrodes in a fixed spacing arrangement and filling the space with a liquid mixture. The electrodes are sealed to provide a closed compartment containing the liquid mixture and having the electrodes in contact with the liquid mixture. As can be seen, this cell consists of two substrates, each with a conductive material, or two interdigital electrodes (in-place switching- {in-place switching
ng: "IPS"}).

Liquid crystal cells manufactured according to the present invention include panel displays; transparencies for aerial, outer space, land, water and underwater vehicles; transparencies for residential and commercial buildings, containers and lenses. , For example, it can be used as a transparent material for eyewear. As can be appreciated, when the electrode of the present invention is used in eyewear, it is preferred that the electrode be unidirectionally wiped to advance from the darkened polarization state to the bleached unpolarization state.

DESCRIPTION OF THE INVENTION The present invention relates to improved electrodes for liquid crystal cells. The liquid crystal cell utilizes an AC electric field applied across the electrodes to control the alignment of the liquid crystals. An electrochromic cell is one in which a DC current is applied between electrodes to control darkening and bleaching of an electrochromic material.

To understand the present invention, consider currently available liquid crystal cells (prior art). Referring to FIG. 1, there is shown a liquid crystal cell 10 representative of the prior art.
The liquid crystal cell 10 includes a pair of electrodes 12 and 14 held in a spaced-apart relationship by a plurality of spacers 16 (only one shown in FIG. 1). Electrode 1
The edges 2 and 14 (only the edges are shown in FIG. 1) are used in the art to seal the compartments of the liquid crystal cell device to provide a sealed compartment 20 between the electrodes. It is sealed with an epoxy resin 18 of the type. Compartment 20 contains homogeneously aligned liquid crystals (designated by the numeral 22 in Figures 1-3) and dichroic dye molecules (of the type used in the art of making nematic guest-host liquid crystal cells). 1 to 3) (designated by the numeral 24) and each of the electrodes 12 and 14 is connected by a circuit 26, which at one end is connected to one of them, for example to the electrode 12. It includes a power supply 28 connected by a wire 30 and at its other end to a switch 32. Switch 32 is connected by a wire 34 to the other electrode, for example electrode 14. Switch 32 connects the electrodes "Power on" or "power off" the liquid crystal cell from a darkened state ("power off" state cell) to a bleached state ("power on" state cell). The power supply is preferably an AC power supply, as can be appreciated, and a DC power supply can also be used in the practice of the present invention; Deteriorate the cell.

A prior art cell of the type shown in FIG. 1 was processed in a laboratory environment. Electrodes 12 and 14 each included a glass substrate 36 having an indium tin oxide (“ITO”) coating 38 and a polyimide layer 40 adhered to the ITO coating 38. The ITO coating was applied by the magnetron sputter vacuum deposition (“MSVD”) method. The polyimide layer 40 is made of liquefied polyimide.
It was deposited or applied onto the ITO coating by spin-coating on the ITO coating, followed by heat treatment of the applied polyimide to polymerize to provide a polyimide layer 40 over the ITO coating 38. Electrodes 12 and 1
4 were then placed side by side with the polyimide layer side facing up. The entire surface of each of the polyimide layers was rubbed in one direction with a felt cloth, that is, unidirectional wiping or unidirectional rubbing. Each polyimide layer was rubbed 5 times in one direction. On one surface of the scraped polyimide surface of the electrode, 2-propanol and E. M. The mixture was spin coated with an 8 micron diameter glass fiber cylindrical rod sold by EM Industries Inc.

Thereafter, one of the electrodes was rotated 180 degrees and inverted to overlay the other electrode with the scraped polyimide surfaces facing each other; the sides of each electrode were aligned with each other and each The ends of the electrodes have an AC power source 28 connected to the wires 30 and 34.
Were arranged offset from each other to provide areas for connecting electrodes 12 and 14 and for capillary filling of each compartment. Spacer 16 (only one shown in FIG. 1) holds electrodes 12 and 14 in a spaced relationship to one another to provide compartment 20. U of the type used in this technical field
Sealed with V-curable epoxy resin. The electrodes, which are held in a fixed spacing relationship by the epoxy resin 18, are heated by any conventional method to a temperature above the isotropic temperature of the liquid crystals in the liquid mixture. The liquid crystal used was E. M. Industries Catalog No. It was of the type sold at E-7. The liquid mixture contained dichroic dye dissolved in the liquid crystal. The liquid mixture was heated to a temperature in the range 58-90 ° C. The liquid mixture was capillary filled by placing droplets of the liquid mixture of liquid crystal and dichroic dye along a pair of staggered ends of the unsealed electrodes in a heated compartment. The electrode assembly was allowed to cool to room temperature and the open end of the compartment was sealed with an epoxy resin, such as a 5 minute curable epoxy resin of the type used in the art to seal the compartment of a liquid crystal cell. . The liquid mixture upon heating is in the isotropic state, but upon cooling it progresses to a homogeneously aligned nematic state (parallel to the rubbing direction), as shown in FIG.

The present invention involves using electrodes that do not have a polyimide layer. More specifically, and with reference to FIGS. 2 and 3 when needed, they show a liquid crystal cell 50 having the features of the present invention. The liquid crystal cell 50 has a spacer 1
6 (only one shown in FIGS. 2 and 3) includes electrodes 52 and 54 held in a spaced relationship. In this case, the sides and ends of electrodes 52 and 54 are sealed with epoxy resin 18 to provide a sealed compartment 56. A compartment 56, similar to compartment 20 of FIG. 1, is filled with a liquid mixture having liquid crystals 22 and dichroic dye molecules 24, for example of the type discussed above. For a 2 inch (5.08 centimeter, “cm”) square electrode, a drop of liquid mixture is placed at the open end of the compartment, eg, the staggered end, and the liquid is capillaryly moved into the compartment. It is normal to move to. For electrodes with dimensions greater than 2 inches (5.08 cm), for example 4 inches (10.16 cm) square or larger,
The arrangement shown in FIG. 4 is recommended for faster filling of the compartment. More particularly, when filling large compartments, such as 4 inch (10.16 cm) square or larger compartments, on a hot plate, it is important that the liquid crystal does not move too slowly forward. Otherwise there will be bubbles.

Referring to FIG. 4, two adjacent sides 66 and 6 of one electrode 70.
8 are arranged offset from the two adjacent sides 72 and 74 of the other electrode 76. The overlapping portions of the electrodes are sealed at 78 with an epoxy resin of the type used in the art. A droplet of liquid mixture is applied along two adjacent sides 68,74 and 66,72 to fill the compartment 80 with capillary action.

As can be appreciated, the present invention is not limited to the composition of liquid mixtures; more particularly, the liquid mixtures include, in addition to liquid crystals and dichroic dyes, chiral nematic liquid crystals, chiral components, thermochromic materials and / or It may include a photochromic material of the type discussed above under the Summary of the Invention. Furthermore, the invention is not limited to liquid mixtures; for example polymer-based liquid crystal systems can be used in the practice of the invention.

Electrodes 52 and 54 embodying features of the invention include a substrate 58 having a coating 60 incorporating features of the invention. One of the substrates 58 can be made of a transparent material, but more often both substrates 58 are both made of a transparent material. In the practice of the present invention, the substrate is made of any material, such as clear, tinted coated glass, or photochromic glass; clear, tinted plastic, or photochromic plastic; metal, and / or glass fiber reinforced plastic. Can be Furthermore, sun-controlled glasses of the type known in the art, eg having low UV transmission, low total solar energy transmission and low infrared transmission, can also be used in the practice of the present invention. Although the present invention may be practiced with a substrate of any material, the substrate material and epoxy resin 18 should be chosen to provide a liquid tight compartment for containing the liquid mixture in compartment 60. is there. In the case of polymer-based liquid crystal systems, it may not be necessary to seal the compartment. While it is preferred to use transparent soda lime silica glass in the practice of the present invention, the present invention contemplates using one electrode made of soda lime silica glass and the other electrode made of a non-transparent substrate. is doing. In this example, but without limiting the invention, the non-transparent substrate may have a reflective surface or coating under the coating 60.

In the practice of the invention, coating 60 is a conductive coating and an alignment layer for liquid crystals. While not limiting the invention, the preferred coating is a tin oxide coating which may include dopants such as fluorine and / or antimony. The ITO shown below can be used when made according to the invention discussed below. Conductive coatings, such as tin oxide coatings, can be provided in any convenient manner, such as, but not limited to, the invention, to name a few, chemical vapor deposition (CVD), physical vapor deposition (PVD). ) Method, combustion chemical vapor deposition (CCVD) method, spray pyrolysis method, pulse laser deposition method, plasma spraying method, filtered laser arc method, pulse dc glow discharge method,
Plasma arc deposition method, plasma CVD method, metal organic CVD method, ion assisted deposition method, hollow cathode deposition method, laser assisted deposition method, reactive magnetron sputtering method, pulse reactive magnetron sputtering method, pulse magnetron sputtering method, plasma CVD method , Can be deposited by electron cyclotron resonance CVD method. As can now be understood, the material of the substrate should be chosen so that it does not decompose during the deposition or application of the conductive and alignment coating. In the practice of the present invention, the preferred substrate material is glass, and the conductive and aligning coating is pyrolytically applied or coated onto the glass substrate. As will be appreciated, the sheet resistivity of the electrodes is not a limitation of the present invention; however, as the area of the electrodes in contact with the liquid mixture increases, an electrode with a lower sheet resistivity will be included. It is desirable to let Cells with sheet resistivities in the range of 3-127 ohms / square were made.

The invention was carried out using a soda-lime-silica glass piece cut from a 3 mm thick glass ribbon produced by the float process. As the glass ribbon travels through the chamber above the molten metal bath, the glass ribbon is incorporated by reference in US Pat.
It was coated with a low E-coating of the type and method disclosed in 356,718. PPG Industries Inc.
This coated glass, which is of the type sold under the trade name of 500 coated glass, has an amorphous mixed SiO ₂ —SnO ₂ coating layer applied by pyrolysis to its glass ribbon, and the amorphous mixed glass. in which SiO ₂ -SnO ₂ fluorine-doped crystalline tin oxide on the coating (SnO ₂ -F) coating layer is deposited. The sheet resistivity of a layer of Sungate 500 coated glass is about 20 ohms / square and about 63 ohms for Sungate 300 coated glass (fluorine-doped crystalline tin oxide deposited on glass by pyrolysis). . A glass plate was cut from the glass ribbon. Some glass plates cut from glass ribbons were stored for 3 years before they were used to make electrodes incorporating the features of the present invention. These glass sheets were stored with a release medium of polymer beads between the sheets. For a discussion of polymeric beads, see the relevant description in US Pat. No. 4,530,889, the disclosure of which is incorporated herein by reference. Initially, it was suspected that aging might have an effect on the coating, but subsequently the electrodes made showed that aging had no noticeable effect on the performance of the electrode coated glass in the practice of the present invention. It was

The following is a discussion of the production of samples incorporating the features of the present invention (initial samples) using glass stored for 3 years. From the glass plate two 2 "(
5.08 cm) square glass coupons were cut and the coated surface was sprayed with a 50:50 v: v solution of 2-propanol: deionized water, and the coated surface was covered by TEXWIPE Company LLC. Trademark name, TechniCross ^TM (Tech
niCloth ^™ ), which was cleaned by wiping and drying with a polyester-cellulose wipe, Kimwipe, and unidirectional wiping 5 times with a 2-propanol wet felt cloth. The liquid crystal cell is electrically connected to each of the electrodes with the compartments having a size of 2 ″ × 1 · 3/4 ″ and the extension of each of the electrodes on the opposite sides of the compartment 60 being ¼ ″. 2 was assembled in a similar manner to the liquid crystal cell 50 shown in Figure 2. A heated liquid mixture of E7 liquid crystal and 2 weight percent G-472 dichroic dye. Was prepared and flowed into the heated compartment previously discussed for direct contact with the tin oxide coating, which compartment was sealed as previously discussed and an AC power source was connected to the electrodes. 2-20 volts and 50-60
When the Hertz AC voltage or AC field is powered on (see Figure 3),
The luminous transmittance (Lta) was 44% in the bleached state, and when the AC field was powered off, the luminous transmittance (Lta) was 26% in the darkened state. Referring to FIG. 3, at power-on, the longitudinal axis of the crystal 22 and the dichroic dye 24 is defined by the crystal and dichroism remaining with their long axes parallel to the coating shown in FIG. Except for the thin molecular layer with the dye, it was perpendicular to the tin oxide. When the liquid crystal cell was powered off, it went into an unbleached (dark) state, and when viewed through a linear polarizer, the linear wiping direction of the coating was observed as indicated by the position of the dichroic dye. . For additional liquid crystal cell processing, the wiping direction during cleaning of the coating was circular. When viewed through a linear polarizer with this cell in the unbleached state, its circular wiping direction was indicated by the location of the dichroic dye.
From these observations, liquid crystals and dichroic dyes follow the wiping direction during cleaning of the coating, or the majority of contaminants on the coated surface of the crystalline tin oxide coating are removed, and the liquid crystal molecules Would be aligned with the texture of the coating, or some combination of these effects would be obtained.

Table 1 shows a liquid crystal cell (LCC) N made according to the present invention using the electrodes of the present invention.
o. The details of 1 to 7 are shown. LCC No. No. 6 was made by using coated glass stored for about 10 years or more, and LCC No. 6 was used. 7 was made with coated glass stored for less than a year. LCC No. 1 to 3 and 5 to 7 are nematic guest-host liquid crystal devices, which are linear polarizers in the darkened state. LCC / N
o. 1-3 and 5-7 functioned equivalently; more specifically, the color transmitted in the darkened state was uniform as seen by the naked eye or by a linear polarizer. LCC No. Four
Is a twisted nematic guest-host liquid crystal cell that is not a linear polarizer in the darkened state. LCC No. 4 performed the same function as LCC having a polyimide layer and a twisted nematic guest-host liquid crystal.

[0023]

[0024]

Note 1: CB15 is an E. M. It is a chiral molecule obtained from Industries. Percentages are weight percentages based on the total weight of the liquid mixture.

Note 2: G-472 is a blue dichroic dye and G-202 is a purple dichroic dye. Each of them is the Nippon Kankoh Shrine Research Institute in Okayama, Japan.
ikiro Kenkyusho). These dyes were 1 weight percent based on the total weight of the liquid mixture.

Note 3: All compartments of the sample except for the following points have a pair of opposed sides sealed,
It was filled by filling the compartment (capillary filling) and then sealing the remaining sides of the compartment. Sample 3 was filled by staggering the plates to give a 13/4 "square compartment. Two adjacent sides were left open to receive the liquid mixture, and their adjacencies. The part of the side to be sealed was sealed and the liquid mixture flowed through the compartment and out the opposite corner (see Figure 4).
.

LCC No. The 3-device was filled simultaneously from two adjacent edges. The device was then cooled but not powered. The device is then reheated to an isotropic state and cooled to a nematic state with 24V AC.
Powered by. After cooling to room temperature, the device was powered. The function of the device was the same as that made with unidirectional filling.

LCC No. Upon cooling to the 4-nematic state, the liquid crystal-dye mixture had a hazy appearance. But when the device is turned on (bleached), the device is not cloudy. Looking at the polarizer rotated 90 degrees back and forth-there is very little lightening and darkening, which acts as a natural polarizer.

LCC No. 5-Device is LCC No. Functions the same as devices 1 to 4.

LCC No. When observed with a 6-linear polarizer, scratches due to cleaning were observed and the darkened state appeared uniform to the naked eye. These scratches may be the result of surface damage as a result of storage and handling during storage, but the surface damage could not be completely removed by subsequent cleaning; LCC No. Functions the same as devices 1 to 4.

[0032]   LCC No. 7-Device is LCC No. Functions the same as 1 to 4.

Referring to Table 2, LCC No. Reference numeral 8 represents a conventional technique. LCC / N
o. No. 9 was cleaned, but it was not rubbed, and when viewed with the naked eye, LCC No. Looks similar to 8. That is, they were uniformly dark in the off state (no voltage applied) and uniformly bleached in the on state (2-20 volts, 50-60 hertz voltage). However, when viewed through the linear polarizer in the off state, the light was not completely blocked in any orientation of the linear polarizer. Instead, when the linear polarizer was given a rotation similar to how the surface was rubbed and cleaned, bright and dark patterns were observed. These observations indicate that the liquid crystal and the dichroic dye are aligned parallel to the glass surface, but not unidirectionally in any one direction, so the device is not a linear polarizer. The linear polarizer was unidirectionally wiped and cleaned, but was not unidirectionally rubbed. Obtained by 10. The alignment of the liquid crystals and dyes was further improved by rubbing with dry cotton cloth or velvet 10 times (see LCC No. 11). LCC No.
No. 11 looks uniform to the naked eye, and LCC No. It was an improved linear polarizer as compared with 10.

From Table 2 and the following discussion, it becomes clear how the cleaning method affects how the liquid crystal molecules align on the surface.

LCC No. 12 and 13 were plasma cleaned. LCC No. 12
It was not unidirectionally rubbed after plasma treatment, but it was an acceptable linear polarizer. Plasma treated and unidirectionally abraded LCC No. 13 is LCC N
o. It was an improved linear polarizer as compared with 12. LCC No. 14 and 15
Is cleaned with ultrasonic waves. LCC No. No. 14 was not unidirectionally rubbed and was a defective linear polarizer. LCC No. When 15 was ultrasonically cleaned and unidirectionally rubbed, it became a linear polarizer. LCC No. Based on 9-15, it is concluded that unidirectional abrasion after the cleaning process gives better linear polarizers.

Cleaned by wiping with solvent followed by unidirectional rubbing
LCC No. 16 did not appear uniform in color to the naked eye; parallel homeotropically aligned irregular areas were observed. It was cleaned by ultrasonic waves, but was not rubbed. No. 17 is LCC No. It looked like 16. Ultrasonically cleaned, then unidirectionally rubbed LCC No. 18, the color looks uniform to the naked eye,
Acted as a linear polarizer. From the above, it is concluded that ITO glass also makes it possible to obtain a homogeneous alignment without a polyimide layer when ultrasonically cleaning in a detergent bath.

[0037]

Note 1: Liquid Crystal of Kent State University
Electrodes obtained from the Institute (Liquid Crystal Institute).

[0039] Note 2: irregular with a solvent wiping: First 2-propanol, acetone, or 1: 1 volume ratio of 2-propanol: deionized water (DI) was sprayed onto the substrate and then Kimwipe scan ^TM (Kimwipes ^TM ) Wipe with a wiper or TechniCross ^TM wiper to dry. The substrate is then randomly wiped with a Kimwipes ^™ wiper moistened with 2-propanol or acetone.

Note 3: A glass plate is an interleaving material that separates adjacent glass surfaces.
).

Note 4: Solvent unidirectional wiping: First spray a substrate with a 1: 1 volume ratio of 2-propanol: (DI) water and wipe with a Kimwipes ^™ wiper or Technicloth ^™ wiper to dry. The substrate is then unidirectional wiped with a velvet cloth saturated with 2-propanol or acetone.

Note 5: Plasma: First rinse the substrate with plenty of DI water, then blow dry with nitrogen. Next, the sample is processed by SPI ^™ Suppliers Plasma Prep II.
Exposure to oxygen plasma for 20 minutes in a device (SPI ^™ Suppliers Plasma Prep II unit).

Note 6: Ultrasound: First rinse the sample with plenty of DI water. It is then ultrasonically cleaned for 20 minutes in an aqueous detergent bath (Dart 210, pH 2.9, 50 ° C). Finally, it is washed with DI water and blown dry with nitrogen.

[0044]   Note 7: Made by PPG Industries.

Note 8: LCC No. The liquid crystal mixture of 8 to 18 is E-7 and blue dichroic dye G47.
It was a mixture with 2.

Table 3 provides various types of conductive layers applied on glass substrates with a range of sheet resistivities (3 to 127 ohms / square), and acceptable linear polarizers in the darkened state. Figure 3 shows different surface treatments incorporating the features of the present invention that result in acceptable nematic host-guest liquid crystal cell devices. Table 3 further shows that higher% transmission of the electrodes generally results in a greater change in luminous transmission from the darkening stage to the bleaching stage (LCC No. 22 and 2).
4).

As can be appreciated, the present invention is not limited to electrode design or the number of conductive substrates used. For example, and with reference to FIG. 5, there is shown a substrate 88 and a conductive substrate 86 having two interdigital electrodes 90 and 92 connected to the power supply 28 previously discussed. Although two interdigital electrodes are shown in FIG. 5, the present invention also contemplates having more than two electrodes on a surface.

[0048]

A) Spray with 1: 1 volume ratio of 2-propanol: DI water and wipe dry with Technicros ^™ wiper (Texswipe ^™ ). Rubbing with a cotton pad 10 times in one direction.

B) Wash with DI water, followed by 20 minutes ultrasonic cleaning in Dirt 210 detergent solution at pH 2.9 heated to 40 ° C. It is then rinsed with DI water and blown dry with house nitrogen. Unidirectionally rub with synthetic velvet 10 times.

[0051]   Note 1: Pyrolysis powder spray method.

Sungate 1000 is a glass substrate with an MSVD coating that has two layers of silver separated by a dielectric film.

Sungate 100N is a glass substrate having an MSVD coating with one silver layer and a dielectric film on each side.

Sungate 200 is a pyrolytically coated glass substrate having fluorine-doped tin oxide on one surface and a reflective film on the other surface.

Solar Van 55 glass is glass with antimony-doped tin oxide deposited by pyrolysis.

Sungate and solar vans are manufactured by PPG Industries Ohio
ustries Ohio, Inc.), and is a product sold by PPG Industries, Inc.

As can be appreciated, the present invention is not limited by the examples provided, but only by the claims below.

[Brief description of drawings]

[Figure 1]   FIG. 6 is a cross-sectional view of a prior art liquid crystal cell in which no electric field is applied across the electrodes.

[Fig. 2]   FIG. 6 is a cross-sectional view of a liquid crystal cell of the present invention in which an electric field is not applied across the electrodes.

[Figure 3]   FIG. 3 is a view similar to the cross-sectional view of FIG. 2, with an electric field applied across the electrodes.

FIG. 4 is a top view of a pair of electrodes mounted in a fixed positional relationship with each other for capillary filling of a liquid mixture into a compartment between the electrodes.

FIG. 5 is a top view of a substrate having two interdigital electrodes that can be used in the practice of the present invention.

[Procedure for Amendment] Submission for translation of Article 34 Amendment of Patent Cooperation Treaty

[Submission date] June 27, 2001 (2001.6.27)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Contents of correction]

[Claims]

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), OA (BF, BJ , CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, K E, LS, MW, MZ, SD, SL, SZ, TZ, UG , ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, C N, CR, CU, CZ, DE, DK, DM, EE, ES , FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, K R, KZ, LC, LK, LR, LS, LT, LU, LV , MA, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, S I, SK, SL, TJ, TM, TR, TT, TZ, UA , UG, UZ, VN, YU, ZA, ZW F term (reference) 2H090 HB03Y HB18Y HC03 HC08                       HC10 JB02 JB03 LA01 MB01                 2H092 HA04 KB01 KB14 KB23 NA27                       PA02                 5C094 AA43 BA43 EA04 EA07

Claims (22)

[Claims] 1. A liquid crystal cell of the type having a pair of electrodes spaced apart from each other and a sealed portion providing a compartment therebetween, and having a liquid mixture in the compartment. And wherein in the liquid crystal cell the electrodes have a polyimide surface in contact with the liquid mixture: the pair of electrodes has a conductive and aligned surface in contact with the liquid mixture. The above liquid crystal cell, which is improved. 2. The cell of claim 1, wherein the electrically conductive and aligned surface is selected from the group comprising tin oxide and indium oxide. 3. The cell of claim 2, wherein the coating is a tin oxide coating having a dopant material selected from the group consisting of fluorine and antimony and mixtures thereof. 4. The cell of claim 3, wherein the substrate is a glass substrate, the electrode comprises a tin oxide coating, and the dopant material is fluorine. 5. The cell of claim 4, wherein there is a tin oxide / silicon oxide gradient layer between the tin oxide and the glass substrate. 6. The cell of claim 5, wherein the electrode comprises a pair of substrates, each substrate having a conductive and aligned surface. 7. The cell of claim 6, wherein the coating is applied pyrolytically. 8. The cell of claim 1, wherein the electrode comprises a substrate, the substrate having at least two discrete, electrically isolated conductive regions thereon. 9. The cell of claim 1, wherein the coating is a stacking coating having a silver layer between dielectric layers. 10. The cell of claim 9, further comprising a primer layer between one of the dielectric layers and the silver layer. 11. The cell of claim 10, wherein the coating is applied by sputter deposition. 12. The cell of claim 3, wherein the coating is a tin oxide coating and the dopant material is antimony. 13. The cell of claim 12, wherein the dopant is a mixture of antimony and fluorine. 14. The cell of claim 1, wherein the coating is crystalline and its surface is unidirectionally abraded. 15. The substrate is plastic and the conductive coating is
The cell according to claim 1, which is ITO. 16. The cell of claim 1, wherein the light transmittance of the cell changes upon application of an AC voltage across the electrodes. 17. A method of manufacturing a liquid crystal cell comprising the steps of: applying a conductive coating to a substrate; providing a closed compartment having a liquid mixture therein in direct contact with said conductive coating. The above method. 18. The step of providing a closed compartment comprises: preparing two substrates, one of which has a conductive coating; mounting the two substrates described above with their sides offset from each other; By applying the liquid mixture along two adjacent sides of the substrate between the opposite surfaces of the substrates; and sealing the gap between the substrates to provide a closed compartment. The method according to claim 17. 19. The step of applying a coating is accomplished by applying at least two discrete and insulated conductive regions on one substrate,
18. The method of claim 17, wherein the step of providing a closed compartment is accomplished by mounting the substrate having a conductive region at a distance from a surface of a non-conductive substrate. 20. The method of claim 17, further comprising cleaning the conductive surface. 21. The method of claim 20, wherein the cleaning step comprises the step of rubbing a solvent saturated cloth in a direction for a selected number of times. 22. The method of claim 18, wherein the spaced apart substrate and the liquid mixture are heated prior to performing the step of applying the liquid mixture.